1. Field of the Invention
This invention relates to a vibration characteristic measuring device adapted to measure the vibration characteristic of, for example, a disk drive suspension.
2. Description of the Related Art
A hard disk drive (HDD) is known as a device for accessing data stored in a rotating magnetic disk. A disk drive suspension (hereinafter referred to simply as the suspension) is used for the HDD. A slider is disposed on the distal end portion of the suspension. The slider is provided with a transducer for reading or writing data.
A vibration characteristic measuring device is used to analyze the vibration characteristic of the suspension. As described in, for example, Jpn. Pat. Appln. KOKAI Publication No. 2007-192735 (Patent Document 1), the vibration characteristic measuring device is provided with a laser Doppler vibrometer (LDV). The measuring device disclosed in Patent Document 1 includes a shaker and a metallic mounting block. The shaker includes a shaking section that is reciprocated by an actuator. The mounting block is fixed to a mounting surface of the shaking section. The mounting block is fastened to the mounting surface of the shaking section by a screw member. The suspension to be measured is mounted on the mounting block.
The suspension is mounted on the mounting block. Further, the mounting block is fixed to the shaking section of the shaker by the screw member. The suspension vibrates as the mounting block in this state is shaken at a predetermined frequency by the shaker. The vibration of a slider or the like of the suspension is detected by the LDV. In some cases, vibration modes may appear in a measured waveform obtained in this manner.
FIG. 25 shows a frequency response characteristic (transfer function) of a mounting block of a conventional vibration characteristic measuring device. FIG. 26 shows a frequency response characteristic of a slider of a suspension attached to this mounting block. In FIGS. 25 and 26, the abscissa and ordinate represent frequency and gain (equivalent to amplitude), respectively. In either of FIGS. 25 and 26, the waveform is severely disturbed near a specific frequency (e.g., 26 kHz).
This waveform disturbance is caused by a vibration mode attributable to a resonance of the mounting block. If a vibration mode M appears in a measured waveform of the mounting block, as shown in FIG. 25, a vibration mode M′ also appears in a measured waveform of the suspension, as shown in FIG. 26. These vibration modes hinder an analysis of the vibration characteristic of the suspension. Thus, the vibration mode of the mounting block is expected to be prevented from appearing in the measured waveform of the suspension.